The present invention relates to the field of communications in general and more particularly to Internet Protocol (IP) networks.
The Internet has grown tremendously in the past decade and may overtake traditional telecommunication networks for carrying information. On wired networks, it is possible to make telephone calls using Voice over IP (Vow) technology. Furthermore, the Internet allows access to a variety of other multimedia services such as web access. The proliferation of the Internet and wireless technology has led to a merging of the two.
The Global System for Mobile (GSM) Communication cellular standard was developed to evolve older analog standards such as the Nordic Mobile Telephone (NMT) system to modem spectrally efficient technologies based on digital communications. Over time the GSM system has evolved to support packet radio as well through the General Packet Radio Service (GPRS) network. Further improvement in spectral efficiency has been planned through introduction of the effort named, Enhanced Data rates for Global Evolution (EDGE) of TDMA standards.
The Universal Terrestrial Mobile Telephone System (UMTS) is an evolution of traditional telecommunication networks to support a service-centric architecture. The UMTS system has evolved to support circuit switched and packet switched communication within a single network managed by clearly defined modular components and interfaces. The network may allow easy replacement or improvement of functionality without affecting other components, and aims at providing uniform access to traditional and multimedia services using a variety of access methodologies. Although the UMTS system was developed around the Wideband Code Division Multiple Access (WCDMA) air-interface as defined by the UMTS Terrestrial Radio Access Network (UTRAN), the GSM/EDGE standardization effort has resulted in the GSM/EDGE Radio Access Network (GERAN) being considered as an alternative access network to the UMTS Core Network. Further evolution of the UMTS core network concentrates on developing the all-IP network, aiming at support of end-to-end multimedia services over all attached radio access networks.
Although audio codecs and video codecs are, typically, capable of adapting their source rates, that rate change will, typically, occur over a much longer time frame than needed to follow the effects of environmental changes on the communications channel.